Transistor devices, especially field-effect transistor devices, are widely used as electronic switches in a variety of electronic applications, such as automotive, industrial, household, or consumer electronic applications. In some applications it is desirable for the transistor device to have a reverse conducting capability. That is, the transistor device operates like a switch, that can be switched on and off, when a voltage with a first polarity (forward voltage) is applied between load terminals (drain and source terminals) of the transistor device, and the transistor device always conducts a current when a voltage with a second polarity (reverse voltage) is applied between the load terminals.
Some types of MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) and JFETs (Junction Field-Effect Transistors) have an internal diode (body diode) between the source and drain terminals. The internal body diode provides for the reverse conducting capability. However, the forward voltage of the internal diode causes losses when the transistor device is reverse conducting. Especially in transistor devices implemented with wide-bandgap semiconductor materials, such as SiC (silicon carbide) or GaN (Gallium nitride), the forward voltage and, therefore, the losses, are relatively high. The forward voltage of a SiC diode is about 3.5V, which is about five times the forward voltage of a Si (silicon) diode (which is about 0.7V).
There is therefore a need to provide an electronic circuit with a transistor device, in particular a normally-on transistor device, in which the transistor device has a reverse conducting capability and has low losses in the reverse conducting state.